Louisiana researchers successfully spawn captive alligator gar

Alligator gar often used as an indicator to determine health of an ecosystem.
With numbers dwindling in the Ohio and upper Mississippi river systems, the scientific community is concerned about the future of this ancient fish.
LSU AgCenter researchers have successfully bred the fish in captivity.

Craig Gautreaux, LSU AgCenter | Jun 01, 2012

Alligator gar are often used as an indicator by fisheries biologists to determine the health of an ecosystem. With their numbers dwindling in the Ohio and upper Mississippi river systems, the scientific community is concerned about the future of this ancient fish.

In order to better understand alligator gar, researchers with the LSU AgCenter’s Aquaculture Research Station and Nicholls State University are spawning gar in tanks to acquire brood stock for additional research projects.

Last year, the gar did not lay any eggs, and researchers believe that the stress of being moved to new homes may have been the problem.

“When you handle fish like this, you have to be really careful of their own stress,” said Chris Green, an AgCenter researcher at the Aquaculture Research Station. “When they get stressed out, they can reabsorb their eggs, and they can fail to spawn.”

Research involves an element of persistence, and this year’s spawn was a success.

While alligator gar are disappearing in other river systems, these gar will not be used for restocking according to Green. “We’re not actually interested in distributing theses larvae for restoration because we don’t want to mix these coastal genes with the main Ohio and Mississippi River (genes).”

Louisiana’s gar populations are healthy compared with other states.

Researchers point to two main reasons why they believe gar are disappearing: habitat loss and overfishing. Many researchers feel that habitat loss is playing a much larger role than fishing.

Gar like to spawn in floodplains, and they typically spawn in flooded fields depositing their eggs in flooded grasses. To mimic these conditions, cheerleader pompoms were suspended in the research tanks.

Green said that some of the largest gar in captivity are nearly 70 pounds, and a gar this large could lay up to 50,000 eggs.

Contrary to their reputation and ferocious appearance, alligator gar are quite docile. “Gar get a bad rap as far as being a river monster, as being a voracious fish. You can get into these tanks right now with these gar, and they are not going to eat you,” Green said.

The alligator gar the researchers used for spawning came from two places in Louisiana. One population was captured near the Rockefeller National Refuge in Cameron Parish, and the others were caught in Golden Meadow in Lafourche Parish. Alligator gar can thrive in both freshwater and saltwater environments.